Two populations of Pseudobagrus aurantiacus (Temminck and Schlegel) are discontinuously distributed in Kyushu and the districts from Kanto north.These two geographically isolated populations were analyzed karyologically as well as biochemically. Distinct differences in the karyotypes were observed between two populations indistinguishable in the morphological characters.The karyotype of the Kyushu population has a diploid number of 48 consisted of 10 metacentrics, 6 submetacentrics and 8 telo-and subtelocentrcs.While, the karyotype of northern population invariably has 56 chromosomes including 12 metacentrics, 6 submetacentrics and 10 telo-and subtelocentrics. Lactate dehydrogenase was separated into five major components in the respective population.The results of subunit-dissociation and recombination test with salt solution indicated that the five Isozymes are tetramers composed of two subunits encoded in two different loci, A and B.The electrophoretic mobilities of LDH-B isozymes were clearly different between the two populations, the northern population has a markedly fast anodally migrating LDH-B isozyme.Also, esterase of each population is different in the number of components, activity, and mobility.
In February 10, 1974, a strange hawkfish, 47.0 mm in standard length, 56.5 mm in total length, referred to Oxycirrhites typus Bleeker, which has not previously been reported from Japan was taken at a depth of 40 meter on the coast of Izu, Shizuoka Prefecture.The fish is characterized by having peculiar pectoral fin, the lower several rays of which are unbranched and thickened, elongated snout, well-serrated preopercle and the slender body with reddish fretwork.The specimen examined here agrees with Bleeker's holotype and other specimens of the species obtained from some tropical seas of the Indo-Pacific except for larger eye (4.8 in head length for the present specimen, 5.5 to 6.4 for others), fewer serrations of the preopercle (8 instead of 11 to 23), and moderately forked caudal fin (slightly forked fin in the holotype).
A hermaphroditic specimen of mackerel, Scomber japonicus, measuring 35cm in fork length, was collected from off San'in district, the Japan Sea. Its gonad was described with illustration and compared with the known hermaphroditic case in the same species.Histological observation revealed that both testis and ovary might have been functional in this specimen with clear protandric trend.